Improvement in valves or bottoms for separating slate from coal



SAMUEL E. emscom.

Improvement in Valves or Bottoms for Separating Slate from Coal.

No. 119,757. 17;! Patented 00 0,1871.

Witnesses: fnvrenloz JQ' aKZ 7 4 "UNITED STATES it PATENT OFFICE.

SAMUEL E. GBISCOM, OF MAHANOY PLANE, PENNSYLVANIA.

IMPROVEMENT IN VALVES 0R BUTTUMS FDR SEPARATING SLATE FROM COAL.

Specification forming part of Letters Patent No. 119,757, dated October 10, 1871.

To all whom it may concern:

Be it known that I, SAMUEL E. GRIsooM, of Mahanoy Plane, in the county of Schuylkill, and State of Pennsylvania, have invented a new and useful Improvement in Valves or Bottoms for Separating Slate from Coal; and I do hereby declare the following to be a full, clear, and exact description thereof, which will enable others skilled in the art to which it appertains to make and use my invention, reference being had to the accompanying drawing, which is apart of this specification, in which Figure l is an axial section of my improvement, and Fig. 2 a plan of the inside of one of the halves thereof.

The same parts are denoted by the same letters in both figures.

The apparatus. now generally employed for separating slate from coal is a box, consisting of cast-iron walls, into which is let a grating of strong cast iron to form the bottom thereof. The meshing of this bottom grate varies with the size of the coal, the interstices being somewhat larger than the pieces of coal to be cleaned.

The cushion-box or jig thus constructed is suspended in a water-tank, and so connected with machinery that it may receive a rapid vertical vibrating or reciprocating motion of an inch, more or less. In the grated bottom are laid several (generally three) layers of spalls or stones from the bed of a stream. These stones, commonly called the valves or bottoms of the apparatus, are of irregular form, just as they are picked from the river, but should be flattish and larger than the meshes of the grating.

A rapid vibration, generally three hundred and twenty strokes per minute, being communicated by the actuating machinery to the box the coal to be cleaned is run into it at one side. The effect of the jigging movement under water is to separate the coal and slate the slate, being heavier, sinks between the stones and drops out through the grating, while the clean coal works over to the other side of the box, and thence into a suitable receptacle.

The employment of the stone valves is attended with serious objections, which my invention is designed to obviate. Owing to their irregularity of shape the interstices or spaces between them are irregular; whereas the pieces of slate as well as coal being nearly of uniform size the interstices through which they pass should be correspondingly regular to insure their passage. The valves should also be heavier than coal and not lighter than slate, which is not always the case with stone valves of various rock and irregular weight. The rapid wear, also, of the stones, diminishing their sizetill they fall through the grating, their grinding action on the box grating, which is especially destructive in the presence of water; and the difficulty and expense of finding stones of suitable size, not to mention other inconveniences, have induced me to devise the valve about to be described.

My invention consists in an artificial valve or bottom made of gun-metal, iron, steel, or any of the harder metals, or of any sufficiently hard substance.

This valve I prefer to make of oblate spher. oidal form, and in two parts, as shown in the drawing, the part A being made with a collar, on which is a screw-thread to fit the corresponding female screw in the recess or countersink of the part B.

I fill the cavity G between the two parts with such substance that the valve, when filled, may have the required specific gravity. If, for example, the parts A and B be made of artificial stone, or lignum vitae, or of wood covered with thin sheet-metal, I fill the cavity with lead or other heavy material; but if A and B be of metal or other heavy substance I use a lighter filling, such as cork, or the air in the cavity may be exhausted through a hole in the valve, which is then permanently closed.

The cavity 0 may be of any desired form, and the valve may be constructed with more than one cavity; or, when of light material, may be covered with a heavy metal casing instead of loading it internally.

The valve may be of any form, although I consider the spheroidal to be preferable. It may also be cast in one hollow piece, and the cavity filled from outside and then closed; or it maybe cast on a core and the core left in the valve; and, secure by Letters Patent of the United States when made in two parts, any suitable mode of is joining them may be substituted for the screw- The artificial valve or bottom, constructed as collar. herein described.

These valves are applied and operate in the SAM. E. GRISOOM. same manner as thenatural-stone valves hereto- Witnesses: fore described. WM. R. WRIGHT,

What I claim as my invention. and desire to THos. A. BURTT. 

